ellipsis()
  overflow :hidden
  white-space :nowrap
  text-overflow :ellipsis
// 背景图片
bg-image($url)
  background-image: url($url + "@2x.png")
  background-size :100%
  background-repeat:no-repeat;
  @media (-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3)
    background-image: url($url + "@3x.png")
    background-size :100%
    background-repeat:no-repeat;

// 不换行
no-wrap()
  text-overflow: ellipsis
  overflow: hidden
  white-space: nowrap

box-shadow()
  box-shadow 0 0 20px 0 rgba(0,0,0,.10)
